Comment by mrandish | Hacker News Reader

Comment by mrandish | Hacker News Reader

> A first comment is that it would have been better for each individual to have done both "Heads up"and "Tails up" tosses (which was part of the intended protocol, but on this aspect of the protocol there was a miscommunication)

That was a pretty unfortunate error in the experiment. Maybe it doesn't matter but now we don't know. It would also have been nice to have them swap coins halfway to expose any individual per coin biasing. It may seem like an irrelevant thing but I've been a lifelong magician specializing in advanced slight of hand coin magic. I carry a set of coins with me all day, every day and handle them constantly. It started out as practice but evolved into both practice and a kind of fidget toy. I have sets of coins I've probably handled for thousands of hours over decades.

Most people think of coins as immutable but they actually change quite a bit after hundreds of hours of handling. Most advanced coin magicians don't tend to use "trick" coins from a magic shop because they are actually too limiting. The coins I use are completely normal circulated coins but they are very specific because there are subtle differences in how coins handle which, at the most advanced levels, can matter. I have year-matched sets of coins I've carefully assembled because they have the degree of surface wear (sometimes called 'softness') and edge-milling which works best for the style of slights I do. Coins also vary in shape and many aren't quite round. I've actually hired a specialized machinist (aka coin-smith) to 'true-up' the shape and then re-mill the edges of certain coins.

Based on my admittedly unusual experience in handling coins, I suspect that weight, edge and surface variations in individual coins could have a material aerodynamic impact at this statistical level (sub-half a percent). BTW, there are coin magicians who have mastered the ability to flip a normal coin and control the outcome to >95%. While the coin is normal in every way, it does need to be a coin they've specifically trained with. Otherwise the hit rate falls considerably.

That's super interesting! Of note, the book Quicksilver (First book in the Baroque Cycle) goes into a few diatribes about subtle differences in coins in Europe a few hundred years ago; eg coins being valued by metrics other than their face value.

Eg: > “I say, Daniel, is it true what they say, that those coins are perfectly circular?”

> “They are, Isaac—not like the good old English hammered coins that you and I carry in such abundance in our pockets and purses.” ... >“if someone clips or files a bit of metal off the edge of a round coin with a milled edge, it is immediately obvious.”

> “That must be why everyone is melting those new coins down as fast as they are minted, and shipping the metal to the Orient…?” Daniel began,

> “…making it impossible for the likes of me and my friend to obtain them,” Isaac finished.

> “Now there is a good idea—if you can show me coins of a bright silver color—not that black stuff—I’ll weigh them and accept them as bullion.”

> “Bullion! Sir!”

> “Yes.”

> “I have heard that this is the practice in China,” Isaac said sagely. “But here in England, a shilling is a shilling.”

> “No matter how little it weighs!?”

> “Yes. In principle, yes.”

> “So when a lump of metal is coined in the Mint, it takes on a magical power of shillingness, and even after it has been filed and clipped and worn down to a mere featureless nodule, it is still worth a full shilling?”

> You exaggerate,” Daniel said. “I have here a fine Queen Elizabeth shilling, for example—which I carry around, mind you, as a souvenir of Gloriana’s reign, since it is far too fine a specimen to actually spend. But as you can see, it is just as bright and shiny as the day it was minted—”

> “Especially where it’s recently been clipped there along the side,” the lens-grinder said.

> “Normal, pleasing irregularity of the hand-hammered currency, nothing more.”

Are we all in the same book club or something?

A substantial chunk of the books I read are based on HN recommendations, so... yes?

Egghead book club. Neal Stephenson, Greg Bear, Greg Egan…

Go on...

graeber

If you like that book, read the Newton biography "Never at Rest."

Almost certainly Stephenson read it in his research, and he gets the nature of Newton totally correct in fictional form.

Bought!

Imagine being in the room when they realized that, after forty thousand coin tosses, they screwed up the experiment. Oops.

Then it becomes an 80k coin toss experiment :)

This is how ML training goes. My longest run was 2 months before it collapsed.

But did you learn anything?

Results of analysis:

Well it's not like we're gonna run out of undergraduates, just do the experiment again.

Unrelated question: how do your hands look after handling coins so constantly as you do? Is there a slight sheen to them? Do you have less hair on your hands than you normally would, or more?

No, there's no noticeable difference in the skin surface of my hands. Over years of practice, serious coin workers do develop substantial hand muscle strength and joint flexibility but that's not visually noticeable. It's also just a byproduct of practice and not needed for most of what we do. The key physical ability isn't applying force, it's actually enhanced sensitivity. I can feel precisely where the coins are and feel how the weight is shifting as they move. This sensitivity enables precise control which is really the key thing.

The same is true for card magicians, and card handling. I have a lot of things I can do with my hands and joints that aren't something you can see.

Same with enhanced sensitivity. I can fairly accurately tell you how many cards I pick up from a group. It's just practice, once you can do 2, you do 3, all the way up to 10, to 15 to 20.

Is that a kind of subdigitizing?

"Subitizing" ?

Funnily enough, but also not surprising, it's the same for drummers and their preferred type of sticks.

It is called "kinesthesia", which is important in playing musical instruments, sports, flying aircraft, etc. With respect to flying, pilots trained by Army (navy, airforce) develop these skills far better than those directly recruited by carriers from colleges. We can see those results in some fatal crashes (Air France 447, Asiana 214). I am not blaming the pilots. When one flies with the aid of machines (fly by wire, simulators), one doesn't develop the kinesthesia required to get out of tricky situations(when instruments don't work or when instruments misread, etc).

> BTW, there are coin magicians who have mastered the ability to flip a normal coin and control the outcome to >95%.

Now you made[1] me want to rewatch Rosencrantz & Guildenstern Are Dead[2] again...

[1]: https://www.youtube.com/watch?v=C_TfdNAXOwE

[2]: https://www.imdb.com/title/tt0100519/

I missed it when it came out. Dream casting.

Please send us further down this rabbit hole, it sounds fascinating!

What sort of flourishes/fidgets do you find yourself gravitating to most?

What does great sleight of hand coin magic look like? Who do you admire most?

Where should someone get started if they want to explore this?

> What sort of flourishes/fidgets do you find yourself gravitating to most?

There are a huge variety and it's mostly down to personal preference. Popular flourishes include coin rolls and coin stars. Popular slights include dozens of different palms with single and then multiple coins.

> What does great sleight of hand coin magic look like?

Done right it can be absolutely mind-blowing. For an example take a look at some of Danny Goldsmith's videos (https://www.dannygoldsmithmagic.com/). Danny is very, very good but like a lot of specialized skills, those who aren't deeply into it won't be able to notice a meaningful difference between the top 20% of coin workers.

> Who do you admire most?

That's really down to personal taste and style. One unusual thing about magic is that the "best magicians" in the eyes of other experienced magicians are generally people you've never heard of. Fame doesn't really correlate with the pinnacle of skill. While most famous magicians like a David Copperfield are skilled, they would be the first to tell you they can't hold a candle to the most skilled coin workers or card mechanics.

> Where should someone get started if they want to explore this?

For serious coin work, Danny's teaching videos would be a good start. Look for ones he flags as being appropriate for novices. For learning the art of magic in general, I'd suggest not wasting money buying individual "tricks" unless you just want a few easy party tricks to amaze (or annoy) friends with. Most people who get deep into magic discover that the most valuable and broadly applicable knowledge comes from books, videos and live learning (called "sessioning" by close-up workers). I don't buy much magic in recent years because I'm at the point of just perfecting skills, so it's hard to recommend an online store but a safe bet for beginners would be Vanishing Inc. https://www.vanishingincmagic.com/. The guys that run VI are deeply experienced and they seem to avoid selling a lot of the 'crap magic' that looks amazing to novices but isn't actually all that useful. I was at a lecture by the co-founder a few weeks ago and the guy not only has deep knowledge and mad skills, he clearly loves magic and is good at teaching.

If you just want to watch some higher-quality magical performances, I'd suggest Penn & Teller's "Fool Us" show (lots of clips on YouTube). The technical coordinator on that show, Michael Weber, is a long-time magical inventor and author who is well-regarded by other magicians. He and Teller work together to curate the acts that get on the show and you're basically getting to see some top notch talent hand selected by guys who know the difference.

> BTW, there are coin magicians who have mastered the ability to flip a normal coin and control the outcome to >95%.

I managed 11 heads in a row with a quarter when I was in high school. I was intentionally going for heads so it was either beginner’s luck or an absurd statistical fluke.

If you're not using a specific technique, that was just a fluke.

I'm not a magician, I just learned this one trick/set-of-tricks (and I'm not 95% success at it either).

Even when not trained if you are basically looking to "repeat" a motion, you can get a reasonably consistent flip. A lot of folks think these far out results are just statistics, but statistics actually tells us how incredibly rare this would be.

11 in a row is perhaps still part fluke without training, but as long as you were trying to do the same thing again not unreasonable.

> BTW, there are coin magicians who have mastered the ability to flip a normal coin and control the outcome to >95%

I guess it depends on coins, but my experience with French coins is that it's extremely easy to get stable outcomes. Without training or anything, if I start with heads, I almost always get heads, and if I start tails, I almost always get tails. I could totally believe that with training, I could pick the result. But if you let me pick the side that is up when tossing, then I can predict the outcome.

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